I'll go a little farther... Common configurations for modems leave the speaker on during handshaking, but turn it off during normal data traffic... When I was doing a lot of modem programming I remember there were ATA commands that would turn off the speaker, or leave it on all the time... Really want to annoy a coworker, leave their modem configured not to turn off the speaker... Now the shrieking is basically the sound protocol that lets both ends know how to communicate... Each sound has its own meaning and I believe is still backwards compatible to 300 baud... (Haven't played with modems since the 14.4 days myself though, so that could have changed with the 56K modems) There are some good books on the topic depending on what you want to know Bill -----Original Message----- From: owner-ietf@ietf.org [mailto:owner-ietf@ietf.org] On Behalf Of David Frascone Sent: Tuesday, June 11, 2002 7:47 AM To: Pankaj Bhandari Cc: Bill Cunningham; ietf@ietf.org Subject: Re: modems Ummm . . . how 'bout: During handshaking the modem's speaker is on. On Tuesday, 11 Jun 2002, Pankaj Bhandari wrote: > Screeching occurs during handshaking. > > During the handshaking, the frequency is audible, thats the reason for screeching. > > > > -----Original Message----- > > From: Bill Cunningham [SMTP:billcu@citynet.net] > > Sent: Tuesday, June 11, 2002 12:53 PM > > To: ietf@ietf.org > > Subject: modems > > > > I know modems communicate on the physical layer by electrical pulses or > > binaries sent on copper wires. Is that screeching you hear electrical > > communication? Computers don't communicate by screeching...or do they? > > > -- David Frascone Winston Peters, a rebel without a caucus.